Hitherto lithia (Li.sub.2 O) -alumina-silicate base ceramics, for example .beta.-spodumen and eucriptite, have been known as ceramics having a low thermal expansion coefficient. Such ceramics are however, unsatisfactory due to their low heat resistance. For example, these ceramics, which have a low thermal expansion coefficient (1.0 .times. 10.sup.-6 /.degree.C.about.3.0 .times. 10.sup.-6 /.degree. C) melt at a relatively low temperature (at 1,400.degree. C or below 1,400.degree. C); therefore the maximum temperature at which they may be used is relatively low. Moreover, ceramics of silicon nitride in which magnesia (MgO) is occluded, have been known as possessing high abrasion resistance. This type of ceramic has therefore been employed for high temperature bearings and the like. However, the abrasion resistance of these ceramics is inadequate for high temperature bearings. During use, abrasion of the ceramics is accelerated due to the powder formed by abrasion from the ceramics themselves.